1. Field of the Invention
The present invention generally relates to an illumination lamp, and particularly to a lampshade of the illumination lamp.
2. Description of Related Art
In recent years, light emitting diode (LED) as a highly efficient light source is widely used in such fields as automobiles, display screens, and traffic lights.
FIG. 14 shows a simulated view of a light field of the LED. The light field of the LED is approximately circular. An intensity of the light field of the LED gradually decreases outwardly along a radial direction. Thus, the light field intensity near the LED is higher, and the light field intensity far from the LED is lower. However, in some cases, when the LED is adopted for a street lamp, as the street being long and narrow, the shape of the circular-shaped light field is different from that of the street. As a result of that, a lighting area of such LED projected on the street is small. Thus, more LEDs are required for lighting the street, resulting in high cost and inefficient of energy. For the foregoing reasons, there is a need in the art for an illumination lamp which overcomes the above-described shortcomings.